<!DOCTYPE html>
<html lang="en">
<head>
    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="robots" content="noindex, nofollow">
    <meta name="googlebot" content="noindex, nofollow">
    <link rel="stylesheet" type="text/css" href="./css/index.css">
    <title>小黑记事本</title>
</head>
<body>
    <!-- 主体区域 -->
    <section id="todoapp">
        <!-- 输入框 -->
        <header class="header">
            <h2>记事本</h2>
            <input type="text" v-model="inputValue" @keyup.enter="add" class="new-todo" autofocus="autofocus" autocomplete="off" placeholder="请输入任务">
        </header>
        <!-- 列表区域 -->
        <section class="main">
            <ul class="todo-list">
                <li class="todo"  v-for="(item, index) in list">
                    <div class="view">
                        <span class="index">{{ index+1 }}.</span>
                        <label>{{ item }}</label>
                        <button class="destroy" @click="remove(index)"></button>
                    </div>
                </li>
            </ul>
        </section>
        <!-- 统计和清空 -->
        <footer class="footer">
            <span class="todo-count" v-if="list.length > 0"><strong>{{ list.length }} items left</strong></span>
            <button class="clear-completed" @click="clear" v-show="list.length > 0">Clear</button>
        </footer>
    </section>
    <!-- 底部 -->
    <footer class="info">
        <p>
            <a href="http://www.itheima.com"><img src="./img/black.png" alt="" srcset=""></a>
        </p>
    </footer>
    <!-- 开发环境版本，包含了有帮助的命令行警告。 -->
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
    <script>
        var app = new Vue({
            el:"#todoapp",
            data:{
                list:["写代码", "吃晚餐", "夜跑锻炼"],
                inputValue: "好好学习，天天向上",
            },
            methods:{
                add:function(){
                    this.list.push(this.inputValue);
                },
                remove:function(index){
                    //console.log(index);
                    this.list.splice(index, 1);
                },
                clear:function(){
                    //this.list = [];  
                    this.list.splice(0, this.list.length);                 
                    //this.list.length = 0; //速度最快，不起作用？
                },
            },
        })
    </script>
</body>
</html>